Replaced some fets in the amp and tore some of the sil-pad in a few places. Was wondering if anyone knew what type I could use to replace it with. Any info would be appreciated...added a pic to help identify the sil-pad type

There are several options other than the silicone pads. The 1mil kapton tape with 2mil silicone adhesive works well for class D amps. The kapton MT material (mcmaster-carr part number 2271K24) works well and is a slightly better thermal conductor (not significantly important for class D amps) but has to be cut to size. Mica insulators work well but are tedious to have to deal with. All of these would be used with thermal heatsink compound.